Molecular characterisation and epidemiology of enterovirus-associated aseptic meningitis in the Western and Eastern Cape Provinces, South Africa 2018-2019

Molecular epidemiology and characterization of enteroviruses detected in cerebrospinal fluid and respiratory samples in Slovenia, 2014-2023

Enterovirus (EV) infections have various symptoms and severe complications, including death. To determine EV prevalence and EV types in Slovenia, data on over 25 000 EV RNA tests for diagnostics and surveillance from 2014 to 2023 were analyzed. Altogether, 3733 cerebrospinal fluid (CSF) and 21 297 respiratory (sentinel and clinical) samples were tested for EV RNA. EV typing was performed on all residual EV-positive CSF samples and on subset of respiratory specimens. Altogether, 1238 samples tested positive for EV RNA: 238 (6.4%) CSF and 1000 (4.7%) respiratory samples. EV-positive patients were predominantly male (p < 0.001). Many EV-positive CSF samples were from infants under 3 months (33.1%), whereas most EV-positive respiratory samples were from children 1 to 2 years old (49.2%). Echovirus 30 (E-30) was most frequent in CSF (33.0%), followed by CV-B5 (13.8%) and E-6 (13.8%). CV-A6 was most frequent in respiratory samples (16.0%), followed by EV-D68 (7.6%) and CV-A5 (7.4%). EV types in CSF and respiratory samples show diverse dynamics, with some outbreaks indicated. A significant difference was found in the EV detection rate between CSF and respiratory samples by age. Various EV types were characterized, showing that some EV types are more neurotropic or cause more severe infections.

Enteroviruses: epidemic potential, challenges and opportunities with vaccines

Enteroviruses (EVs) are the most prevalent viruses in humans. EVs can cause a range of acute symptoms, from mild common colds to severe systemic infections such as meningitis, myocarditis, and flaccid paralysis. They can also lead to chronic diseases such as cardiomyopathy. Although more than 280 human EV serotypes exist, only four serotypes have licenced vaccines. No antiviral drugs are available to treat EV infections, and global surveillance of EVs has not been effectively coordinated. Therefore, poliovirus still circulates, and there have been alarming epidemics of non-polio enteroviruses. Thus, there is a pressing need for coordinated preparedness efforts against EVs.This review provides a perspective on recent enterovirus outbreaks and global poliovirus eradication efforts with continuous vaccine development initiatives. It also provides insights into the challenges and opportunities in EV vaccine development. Given that traditional whole-virus vaccine technologies are not suitable for many clinically relevant EVs and considering the ongoing risk of enterovirus outbreaks and the potential for new emerging pathogenic strains, the need for new effective and adaptable enterovirus vaccines is emphasized.This review also explores the difficulties in translating promising vaccine candidates for clinical use and summarizes information from published literature and clinical trial databases focusing on existing enterovirus vaccines, ongoing clinical trials, the obstacles faced in vaccine development as well as the emergence of new vaccine technologies. Overall, this review contributes to the understanding of enterovirus vaccines, their role in public health, and their significance as a tool for future preparedness.

Global landscape of coxsackieviruses in human health

Coxsackieviruses-induced infections, particularly in infants and young children, are one of the most important public health issues in low- and middle-income countries, where the surveillance system varies substantially, and these manifestations have been disregarded. They are widespread throughout the world and are responsible for a broad spectrum of human diseases, from mildly symptomatic conditions to severe acute and chronic disorders. Coxsackieviruses (CV) have been found to have 27 identified genotypes, with overlaps in clinical phenotypes between genotypes. In this review, we present a concise overview of the most recent studies and findings of coxsackieviruses-associated disorders, along with epidemiological data that provides comprehensive details on the distribution, variability, and clinical manifestations of different CV types. We also highlight the significant roles that CV infections play in the emergence of neurodegenerative illnesses and their effects on neurocognition. The current role of CVs in oncolytic virotherapy is also mentioned. This review provides readers with a better understanding of coxsackieviruses-associated disorders and pointing the impact that CV infections can have on different organs with variable pathogenicity. A deeper knowledge of these infections could have implications in designing current surveillance and prevention strategies related to severe CVs-caused infections, as well as encourage studies to identify the emergence of more pathogenic types and the etiology of the most common and most severe disorders associated with coxsackievirus infection.

Diversity of enteroviruses in cerebrospinal fluid specimens collected from hospitalised patients in the private and public sector in South Africa

Enteroviruses cause a wide range of neurological illnesses such as encephalitis, meningitis, and acute flaccid paralysis. Two types of enteroviruses, echovirus E4 and E9, have recently been detected in South Africa and are known to be associated with meningitis and encephalitis. The objective of this study was to characterize enterovirus strains detected in cerebrospinal fluid specimens of hospitalized patients in the private and public sector to identify genotypes associated with meningitis and encephalitis. From January 2019 to June 2021 enterovirus positive nucleic acid samples were obtained from a private (n = 116) and a public sector (n = 101) laboratory. These enteroviruses were typed using a nested set of primers targeting the VP1 region of the enterovirus genome, followed by Sanger sequencing and BLASTn analysis. Forty-two percent (91/217) of the strains could be genotyped. Enterovirus B species was the major species detected in 95% (86/91) of the specimens, followed by species C in 3% (3/91) and species A in 2% (2/91) of the specimens. Echovirus E4 and E9 were the two major types identified in this study and were detected in 70% (64/91) and in 10% (9/91) of specimens, respectively. Echovirus E11 has previously been identified in sewage samples from South Africa, but this study is the first to report Echovirus E11 in cerebrospinal fluid specimens from South African patients. The genotypes identified during this study are known to be associated with encephalitis and meningitis. The predominant detection of echovirus E4 followed by E9 corresponds with other studies conducted in South Africa.

Emerging concerns of blood-brain barrier dysfunction caused by neurotropic enteroviral infections

Enteroviruses (EVs), comprise a genus in the Picornaviridae family, which have been shown to be neurotropic and can cause various neurological disorders or long-term neurological condition, placing a huge burden on society and families. The blood-brain barrier (BBB) is a protective barrier that prevents dangerous substances from entering the central nervous system (CNS). Recently, numerous EVs have been demonstrated to have the ability to disrupt BBB, and further lead to severe neurological damage. However, the precise mechanisms of BBB disruption associated with these EVs remain largely unknown. In this Review, we focus on the molecular mechanisms of BBB dysfunction caused by EVs, emphasizing the invasiveness of enterovirus A71 (EVA71), which will provide a research direction for further treatment and prevention of CNS disorders.

Neurotropic enteroviruses (Picornaviridae: Enterovirus): predominant types, basis of neurovirulence

Enteroviruses are one of the most common causative agents of infectious diseases of the central nervous system. They are characterized by genetic variability, the ability to infect a wide range of cells, including brain microglial cells and astrocytes, and persist in the central nervous system tissue, causing delayed and chronic diseases. The review presents data on the basis of neurovirulence of non-polio enteroviruses and the most common pathogens causing enteroviral neuroinfections.

Potential airborne human pathogens: A relevant inhabitant in built environments but not considered in indoor air quality standards

Potential airborne human pathogens (PAHPs) may be a relevant component of the air microbiome in built environments. Despite that PAHPs can cause infections, particularly in immunosuppressed patients at medical centers, they are scarcely considered in standards of indoor air quality (IAQ) worldwide. Here, we reviewed the current information on microbial aerosols (bacteria, fungal and viruses) and PAHPs in different types of built environments (e.g., medical center, industrial and non-industrial), including the main factors involved in their dispersion, the methodologies used in their study and their associated biological risks. Our analysis identified the human occupancy and ventilation systems as the primary sources of dispersal of microbial aerosols indoors. We also observed temperature and relative humidity as relevant physicochemical factors regulating the dispersion and viability of some PAHPs. Our analysis revealed that some PAHPs can survive and coexist in different environments while other PAHPs are limited or specific for an environment. In relation to the methodologies (conventional or molecular) the nature of PAHPs and sampling type are pivotal. In this context, indoors air-borne viruses are the less studies because their small size, environmental lability, and absence of efficient sampling techniques and universal molecular markers for their study. Finally, it is noteworthy that PAHPs are not commonly considered and included in IAQ standards worldwide, and when they are included, the total abundance is the single parameter considered and biological risks is excluded. Therefore, we propose a revision, design and establishment of public health policies, regulations and IAQ standards, considering the interactions of diverse factors, such as nature of PAHPs, human occupancy and type of built environments where they develop.

Molecular Characteristics of Enterovirus B83 Strain Isolated from a Patient with Acute Viral Myocarditis and Global Transmission Dynamics

This study determined the global genetic diversity and transmission dynamics of enterovirus B83 (EV-B83) and proposed future disease surveillance directions. Blood samples were collected from a patient with viral myocarditis, and viral isolation was performed. The complete genome sequence of the viral isolate was obtained using Sanger sequencing. A dataset of 15 sequences (from three continents) that had sufficient time signals for Bayesian phylogenetic analysis was set up, and the genetic diversity and transmission dynamics of global EV-B83 were analyzed using bioinformatics methods, including evolutionary dynamics, recombination event analysis, and phylogeographic analysis. Here, we report the complete genome sequence of an EV-B83 strain (S17/YN/CHN/2004) isolated from a patient with acute viral myocarditis in Yunnan Province, China. All 15 EV-B83 strains clustered together in a phylogenetic tree, confirming the classification of these isolates as a single EV type, and the predicted time for the most recent common ancestor appeared in 1998. Recombinant signals were detected in the 5'-untranslated region and 2A-3D coding regions of the S17 genome. The phylogeographic analysis revealed multiple intercontinental transmission routes of EV-B83. This study indicates that EV-B83 is globally distributed. Our findings add to the publicly available EV-B83 genomic sequence data and deepen our understanding of EV-B83 epidemiology.

Dynamics of community-acquired meningitis syndrome outbreaks in southern France

In southern France, cases of community-acquired meningitis syndrome (CAM) are typically clustered as outbreaks with determinants which remain unknown. This 61-month retrospective investigation in Nîmes and Marseille university hospital laboratories, yielded 2,209/20,779 (10.63%) documented CAM cases caused by 62 different micro-organisms, represented by seasonal viral etiologies (78.8%), including Enterovirus, Herpes Simplex Virus (HSV), and Varicella-Zoster Virus (VZV; 1,620/2,209 = 73.4%). Multi correspondence analysis revealed an association of infection with age and sex, with the risk of infection being relatively higher in young men, as confirmed by Fisher's exact test (p < 10^-3). Bacterial meningitis accounted for 20% of cases, mostly caused by Streptococcus pneumoniae (27.4% of cases), Neisseria meningitidis (12.5%), and Haemophilus influenzae (9.5%) with bacteria/virus coinfection (0.9%), and only six cases of documented fungal meningitis. In total, 62.6% of cases, of which 88.7% were undocumented, arose from 10 outbreaks. 33.2% of undocumented cases were aged >60 years compared to 19.2% of documented cases (p < 0.001), and viral infection was more common in the summer (87.5%) compared to other seasons (72.3%; p < 0.001). Outbreaks most often started in Nîmes and moved eastward toward Marseille at a speed of ~9 km/day, and these dynamics significantly correlated with atmospheric temperature, especially during summer outbreaks. In particular, the incidence of Enterovirus-driven outbreaks correlated with temperature, revealing correlation coefficients of 0.64 in Nîmes and 0.72 in Marseille, and its occurrence in Marseille lagged that in Nîmes by 1-2 weeks. Tracing the dynamics of CAM outbreak during this retrospective investigation in southern France yielded a speed of displacement that correlated with the variation in temperature between both cities, and these results provide clues for the next occurrence of undocumented outbreaks.

Molecular characterization of echovirus 9 strains isolated from hand-foot-and-mouth disease in Kunming, Yunnan Province, China

Echovirus 9 (E9) belongs to the species Enterovirus B. So far, 12 whole genome sequences of E9 are available in GenBank. In this study, we determined the whole genomic sequences of five E9 strains isolated from the stools of patients with hand-foot-and-mouth disease in Kunming, Yunnan Province, China, in 2019. Their nucleotide and amino acid sequences shared 80.8–80.9% and 96.4–96.8% identity with the prototype Hill strain, respectively, and shared 99.3–99.9% and 99.1–99.8% mutual identity, respectively. Recombination analyses revealed that intertype recombination had occurred in the 2C and 3D regions of the five Yunnan E9 strains with coxsackieviruses B5 and B4, respectively. This study augmented the whole genome sequences of E9 in the GenBank database and extended the molecular characterization of this virus in China.

Enterovirus Surveillance (EVSurv) in Germany

The major aim of the enterovirus surveillance (EVSurv) in Germany is to prove the absence of poliovirus circulation in the framework of the Global Polio Eradication Program (GPEI). Therefore, a free-of-charge enterovirus diagnostic is offered to all hospitals for patients with symptoms compatible with a polio infection. Within the quality proven laboratory network for enterovirus diagnostic (LaNED), stool and cerebrospinal fluid (CSF) samples from patients with suspected aseptic meningitis/encephalitis or acute flaccid paralysis (AFP) are screened for enterovirus (EV), typing is performed in all EV positive sample to exclude poliovirus infections. Since 2006, ≈200 hospitals from all 16 German federal states have participated annually. On average, 2500 samples (70% stool, 28% CSF) were tested every year. Overall, the majority of the patients studied are children <15 years. During the 15-year period, 53 different EV serotypes were detected. While EV-A71 was most frequently detected in infants, E30 dominated in older children and adults. Polioviruses were not detected. The German enterovirus surveillance allows monitoring of the circulation of clinically relevant serotypes resulting in continuous data about non-polio enterovirus epidemiology.